Edison invented the light bulb many years ago(改为被动语态)
The light bulb__________ __________by Edison many years ago.
第1题:
When replacing a thermostatic expansion valve sensing bulb, it is necessary to
A.apply a light film of oil to increase heat transfer
B.apply a light film of oil to prevent oxidation
C.apply a heavy coating of grease to function as a heat sink
D.carefully coat the device with silicone sealant to reduce the effects of convective cooling
第2题:
A
Man invented a lot of sports equipment. The first true piece was the ball.
Thousands of years ago,in Egypt,the children's favorite game was throwing stones. But a badly thrown stone could hurt a child. Looking for something less dangerous to throw,the peo-ple in Egypt made the first balls.
At first,they used tree leaves to make balls. They used vines(藤) to keep the leaves to-gether. Later they began to use pieces of animals' skin and filled them with some light things.These balls were much better than the old ones.
Before long they invented a lot of ball games,and each had its own rules. They began to play these ball games according to the rules. They thought that ball playing was one of the best ways to teach the young men to be brave and strong.
( )21. The Egyptians invented _________very long ago.
A. many different games with balls
B. throwing stones
C. dangerous games
D. many different kinds of games
第3题:
A.discovered
B.found
C.experienced
D.invented
第4题:
A vessel trawling will display a ______.
A.red light over a white light
B.green light over a white light
C.yellow light over a red light
D.white light over a green light
第5题:
A light used to signal passing intentions must be an ______.
A.all-round yellow light only
B.all-round white light only
C.all-round blue light only
D.alternating red and yellow light
第6题:
Modern handheld digital tachometers operated by counting light pulses returned to the unit by
A.the tach generator
B.either the coupling or shaft
C.a small bulb attached to the shaft
D.a piece of reflective tape
第7题:
How many life buoys________on board with self-igniting light?
A.there exist
B.there is
C.there are
D.are there
第8题:
We introduce ourselves () importers and exporters of light industrial (), having many years experience in this line of business.
A、as,produce
B、like,products
C、as,products
D、like,produce
第9题:
An anchored vessel on pilotage duty must show which light(s) at night?
A.A sternlight only
B.Anchor lights only
C.A white light over a red light only
D.A white light over a red light and anchor lights
第10题: